Accessing the Internet is just second-nature for many of us, and hard to imagine life without it. With this in mind, it may surprise you that 15 percent of U.S. adults say they never go online –according to a new study by Pew Research Center. That percentage actually spikes when you look at people who have less than a high-school education and those that make less than $30,000 per year.

Pew Research has been collecting Internet data use since 2000, back then 48% of Americans weren’t online. In the July survey found that the off-line population has been constantly shrinking since data collection began, but over the last couple of years, the size of this group hasn’t changed much.

“We’ve seen slow but steady adoption progress among a lot of demographic groups that have historically used the Internet in low numbers, such as older adults, or those with low income and educations levels,” said Aaron Smith, Pew’s associate director of research. “With that said, there are definitely still disparities around this issue and Internet usage overall really hasn’t changed measurably in the last two years.

In fact, the Internet non-adoption is still mainly consistent with a series of factors such as age, education, household income and race and ethnicity. Seniors are the majority of hold-outs by age group: about 39% of adults 65+ aren’t online, compared to only 3% of 18 to 29 year-olds.

The survey also indicated that digital gaps among different racial groups are narrowing. Back in 2000, the Internet population was:

72% of Asian-Americans 53% of White-Americans

46% of Hispanic-Americans 38% of African-Americans

This recent survey shows that over the past 15 years, African-Americans have seen the fastest growth with usage approaching 53%.

Those who function better in the digital realm and participate more fully in digitally mediated social life enjoy advantages over their digitally disadvantaged counterparts –a key linkage which social science is only beginning to grasp.